Heat warning devices directly applicable to hot surfaces

Abstract

Heat warning safety device comprising thermochromic ink or epoxy in the form of a heat warning symbol sprayed, stamped, stenciled, silk screened, embossed to the hot surfaces of appliances. The device is invisible when cold and is visible when a threshold temperature is reached. In a second version when cold the device shows only the outline of the warning symbol and when hot shows the full symbol. A plurality of these versions of the devices can be placed on various parts of appliances to maximize the effectiveness of the warning system and to tailor it both to children who need guidance as to where to look for said symbols and to adults as to whom the impact is greatest when the warning symbol appears from a point of invisibility. Alternatively, the warning symbol appears on the lip of a mug and advertises the staying power of the hot liquid therein.

What is claimed is:  
     
         1 . A heat warning safety device attachable to a surface, such as metal or glass, for warning individuals that the surface is hot, comprising: 
 a thermochromic composition shaped in a predetermined symbol or in the background of such symbol which communicates that the surface is dangerously hot, the symbol substantially invisible against a background color of the surface and designed to undergo and maintain a readily perceptible color change so that the symbol is readily visible against said background color whenever and so long as the temperature of the surface exceeds a predetermined temperature,    the thermochromic composition capable of being applied as a liquid directly to the surface in the predetermined shape, capable of remaining on said surface in its predetermined shape in solid form, and capable of withstanding temperatures in excess of 300 degrees Fahrenheit,    the thickness in solid form of said thermochromic composition being such that said thermochromic composition is either faintly visible or invisible when viewed from a line of light tangent to the surface by someone whose attention is not specifically directed to said thermochromic composition.    
     
     
         2 . The device of  claim 1 , wherein the composition is capable of being applied as a liquid directly to the surface by being sprayed, stamped, stenciled, embossed or silk screened onto said surface.  
     
     
         3 . The device of  claim 1 , wherein the thermochromic composition is ink.  
     
     
         4 . The device of  claim 1 , wherein the thermochromic composition is epoxy resin.  
     
     
         5 . A heat warning safety device attachable to a surface, such as metal or glass, for warning individuals that the surface is hot, comprising: 
 a thermochromic composition shaped in a predetermined symbol, the symbol having multiple segments, or in the background of such symbol, which symbol communicates that the surface is dangerously hot to a particular level, each segment except one communicating a different level of a degree to which the surface is dangerously hot and one segment communicating that the surface is not dangerously hot until a predetermined temperature of the surface is exceeded, all segments of the symbol except one substantially invisible against a background color of the surface and at least one segment of said symbol designed to undergo and maintain a readily perceptible color change so that said at least one segment is readily visible against said background color whenever and so long as the temperature of the surface exceeds the predetermined temperature, and a second segment of said symbol designed to undergo and maintain a readily perceptible color change so that said second segment is readily visible against said background color whenever and so long as the temperature of the surface exceeds a second predetermined temperature, said second predetermined temperature being higher than said predetermined temperature,    the thermochromic composition capable of being applied as a liquid directly to the surface in the predetermined shape, capable of remaining on said surface in its predetermined shape in solid form, and capable of withstanding temperatures in excess of 300 degrees Fahrenheit, the thickness in solid form of said thermochromic composition being such that said thermochromic composition is either faintly visible or invisible when viewed from a line of light tangent to the surface by someone whose attention is not specifically directed to said thermochromic composition.    
     
     
         6 . The device of  claim 5 , wherein the composition is capable of being applied as a liquid directly to the surface by being sprayed, stamped, stenciled, embossed or silk screened onto said surface.  
     
     
         7 . The device of  claim 5 , wherein the thermochromic composition is ink.  
     
     
         8 . The device of  claim 5 , wherein the thermochromic composition is epoxy resin.  
     
     
         9 . The device of  claim 5 , wherein the symbol has multiple segments indicating different degrees of dangerously hot and wherein one particular segment is programmed to be active at a time.  
     
     
         10 . A heat warning safety device assembly attachable to multiple surfaces of an appliance, said assembly for warning individuals that one of more of the surfaces are hot, comprising: a plurality of heat alert warning devices including 
 one or more devices of a first type attachable to a first surface of the appliance, said device of the first type comprising a thermochromic composition shaped in a predetermined symbol or in the background of such symbol which communicates that the surface is dangerously hot, the symbol substantially invisible against a background color of the surface and designed to undergo and maintain a readily perceptible color change so that the symbol is readily visible against said background color whenever and so long as the temperature of the surface exceeds a predetermined temperature,    the thermochromic composition capable of being applied as a liquid directly to the surface in the predetermined shape, capable of remaining on said surface in its predetermined shape in solid form, and capable of withstanding temperatures in excess of 300 degrees Fahrenheit, the thickness in solid form of said thermochromic composition being such that said thermochromic composition is either faintly visible or invisible when viewed from a line of sight tangent to the first surface by someone whose attention is not specifically directed to said thermochromic composition, and    one or more devices of a second type attachable to a second surface of the appliance, said device of the second type comprising a thermochromic composition shaped in a predetermined symbol or in the background of such symbol which communicates that the surface is dangerously hot, wherein an outline of the symbol is visible against a background color of the surface and a remainder of the symbol is substantially invisible against a background color of the surface, the remainder of the symbol designed to undergo and maintain a readily perceptible color change so that said remainder is readily visible against said background color whenever and so long as the temperature of the surface exceeds a predetermined temperature, the thermochromic composition capable of being applied as a liquid directly to the surface in the predetermined shape, capable of remaining on said surface in its predetermined shape in solid form, and capable of withstanding temperatures in excess of 300 degrees Fahrenheit, the thickness in solid form of the thermochromic composition being such that said thermochromic composition is either faintly visible or invisible when viewed from a line of sight tangent to the second surface by someone whose attention is not specifically directed to said thermochromic composition.    
     
     
         11 . The assembly of  claim 10 , wherein said assembly also includes one or more additional devices that are of the first type or of the second type attachable to one or more additional surfaces of the appliance.  
     
     
         12 . The assembly of  claim 11 , wherein the thermochromic composition is capable of being applied as a liquid directly to the surface by being sprayed, stamped, stenciled, embossed or silk screened onto said surface.  
     
     
         13 . The device of  claim 11 , wherein the thermochromic composition is ink.  
     
     
         14 . The device of  claim 11 , wherein the thermochromic composition is epoxy resin.  
     
     
         15 . A heat warning safety device assembly attachable to multiple surfaces of an appliance, said assembly for warning individuals that one of more of the surfaces are hot, comprising: a plurality of heat alert warning devices including 
 one or more devices of a first type attachable to a first surface of the appliance, said device of the first type comprising 
 a thermochromic composition shaped in a predetermined symbol, the symbol having multiple segments, or in the background of such symbol, which symbol communicates that the first surface is dangerously hot to a particular level, each segment except one communicating a different level of a degree to which the first surface is dangerously hot and one segment communicating that the first surface is not dangerously hot until a predetermined temperature is exceeded, all segments of the symbol except one substantially invisible against a background color of the surface and at least one segment of said symbol designed to undergo and maintain a readily perceptible color change so that said at least one segment is readily visible against said background color whenever and so long as the temperature of the surface exceeds the predetermined temperature, and a second segment of said symbol designed to undergo and maintain a readily perceptible color change so that said second segment is readily visible against said background color whenever and so long as the temperature of the surface exceeds a second predetermined temperature, said second predetermined temperature being higher than said predetermined temperature,  
   the thermochromic composition capable of being applied as a liquid directly to the surface in the predetermined shape, capable of remaining on said surface in its predetermined shape in solid form, and capable of withstanding temperatures in excess of 300 degrees Fahrenheit, the thickness in solid form of said thermochromic composition being such that said thermochromic composition is either faintly visible or invisible when viewed from a line of sight tangent to the first surface by someone whose attention is not specifically directed to said thermochromic composition, and    one or more devices of a second type attachable to a second surface of the appliance, said device of the second type comprising a thermochromic composition shaped in a predetermined symbol or in the background of such symbol which communicates that the surface is dangerously hot, wherein an outline of the symbol is visible against a background color of the surface and a remainder of the symbol is substantially invisible against a background color of the surface, the remainder of the symbol designed to undergo and maintain a readily perceptible color change so that said remainder is readily visible against said background color whenever and so long as the temperature of the surface exceeds a predetermined temperature, the thermochromic composition capable of being applied as a liquid directly to the surface in the predetermined shape, capable of remaining on said surface in its predetermined shape in solid form, and capable of withstanding temperatures in excess of 300 degrees Fahrenheit, the thickness in solid form of the thermochromic composition being such that said thermochromic composition is either faintly visible or invisible when viewed from a line of sight tangent to the second surface by someone whose attention is not specifically directed to said thermochromic composition.    
     
     
         16 . The assembly of  claim 15 , wherein said assembly also includes one or more additional devices that are of the first type or of the second type attachable to one or more additional surfaces of the appliance.  
     
     
         17 . The assembly of  claim 16 , wherein the thermochromic composition is capable of being applied as a liquid directly to the surface by being sprayed, stamped, stenciled, embossed or silk screened onto said surface.  
     
     
         18 . The assembly of  claim 16 , wherein the thermochromic composition is ink.  
     
     
         19 . The assembly of  claim 16 , wherein the thermochromic composition is epoxy resin.  
     
     
         20 . A heat warning safety device attachable to a surface of a metal heating element, such as a grate, grill or griddle, for warning individuals that the surface is hot, comprising: 
 a thermochromic composition shaped in a predetermined symbol or in the background of such symbol which communicates that the surface is dangerously hot, the symbol substantially invisible against a background color of the surface and designed to undergo and maintain a readily perceptible color change so that the symbol is readily visible against said background color whenever and so long as the temperature of the surface exceeds a predetermined temperature,    the thermochromic composition capable of being applied as a liquid directly to the surface in the predetermined shape, capable of remaining on said surface element in its predetermined shape in solid form, and capable of withstanding temperatures in excess of 500 degrees Fahrenheit,    the thickness in solid form of said thermochromic composition being such that said thermochromic composition is either faintly visible or invisible when viewed from a line of light tangent to the surface by someone whose attention is not specifically directed to said thermochromic composition.    
     
     
         21 . The device of  claim 20 , wherein the surface of the metal heating element that the thermochromic composition is located on is the surface of an outer perimeter base of said metal heating element.  
     
     
         22 . The device of  claim 21 , wherein the composition is capable of being applied as a liquid directly to the surface by being sprayed, stamped, stenciled, embossed or silk screened onto said surface.  
     
     
         23 . The device of  claim 20 , wherein the thermochromic composition is ink.  
     
     
         24 . The device of  claim 20 , wherein the thermochromic composition is epoxy resin.  
     
     
         25 . A heat warning safety device attachable to a surface of a metal heating element, such as a grate, grill or griddle, for warning individuals that the surface is hot, comprising: 
 a thermochromic composition shaped in a predetermined symbol or in the background of such symbol which communicates that the surface is dangerously hot, the symbol designed to undergo and maintain a readily perceptible color change so that the symbol is readily visible against said background color whenever and so long as the temperature of the surface exceeds a predetermined temperature,    the thermochromic composition capable of being applied as a liquid directly to the surface in the predetermined shape, capable of remaining on said surface element in its predetermined shape in solid form, and capable of withstanding temperatures in excess of 500 degrees Fahrenheit,    the thickness in solid form of said thermochromic composition being such that said thermochromic composition is either faintly visible or invisible when viewed from a line of light tangent to the surface by someone whose attention is not specifically directed to said thermochromic composition.    
     
     
         26 . The device of  claim 25 , wherein the surface of the metal heating element that the thermochromic composition is located on is the surface of an outer perimeter base of said metal heating element.  
     
     
         27 . The device of  claim 26 , wherein the composition is capable of being applied as a liquid directly to the surface by being sprayed, stamped, stenciled, embossed or silk screened onto said surface.  
     
     
         28 . The device of  claim 25 , wherein the thermochromic composition is ink.  
     
     
         29 . The device of  claim 25 , wherein the thermochromic composition is epoxy resin.